Comparison of enamel preparations-bevel, chamfer and stair step chamfer on fracture resistance of nano filled resin composites using bulk pack technique-an in vitro study

Abstract

AIM: To evaluate and compare the effect of enamel preparation designs bevel, chamfer and stair-step chamfer on the fracture resistance of nanocomposite. METHODS: The sample group of this study consisted of 72 non-carious permanent maxillary central incisors. The sample is divided into four groups of 18 each. Group, I control Group II bevel preparation, Group III chamfer preparation, group IV stair step chamfer preparation. After the specific preparation, each tooth is filled with nanocomposite using bulk pack technique. The teeth were subjected to fracture resistance test under Universal testing machine and then were examined under a stereomicroscope to evaluate the type of bond failure. The results were subjected to statistical analysis. RESULTS: Results of the One-Way ANOVA revealed a significant difference in the mean peak failure load values of the four different groups. (P < 0.001) Tukey’s Post-Hoc comparison test revealed that there was a significant difference in the mean peak failure load values of the bevel and chamfer preparation. But there was no significant difference between chamfer and stair-step chamfer preparation designs. CONCLUSION: Stair-step chamfer preparation demonstrated comparable values to Chamfer preparation but also involved the removal of less amount of tooth structure adjacent to the fractured edge and good esthetic technique.